The proof of [1]} shows that \(b(0) = 0\)  where \(b(0) = \lim _{\tau \rightarrow 0}b(\tau )\) . Therefore, by eq. (REF ), \(\tau = 0\)  corresponds to the set of points \(t = r\)  on the lightcone at the origin \(\mathcal {O}\) . Lastly, the proof also shows that \(\Omega (0) = \tau _0\) . Since \(\tau _0 > 0\) , eq. (REF ) implies that there is no degeneracy at \(\tau = 0\)  in these coordinates (i.e. the big bang is a coordinate singularity for Milne-like spacetimes). Therefore Milne-like spacetimes admit continuousUsing similar arguments as in [2]}, one can show that Milne-like spacetimes actually admit Lipschitz spacetime extensions through the big bang. This should be compared with the results in [3]}. spacetime extensions through the big bang by defining the extended metric \(g_\text{{\rm ext}}\)  via \(g_\text{{\rm ext}}= \Omega ^2(0)\eta \)  for points \(t \le r\)  and \(g_\text{{\rm ext}}= g\)  for points \(t > r\) .
<FIGURE>